The Carrière des Nerviens Regional Nature Reserve (in French Réserve naturelle régionale de la carrière des Nerviens) is a protected area in the Nord-Pas-de-Calais region of northern France. It was established on 25 May 2009 to protect a site containing rare plants and covers just over . It is located in the municipalities of Bavay and Saint-Waast in the Nord department.
The reserve was created to protect fifteen plants of regional interest and three plant communities listed in the Habitats Directive. Its flora are linked to calcium present in marl. It is located in a transition zone between the oceanic and semi-continental climates and that gives increased biodiversity, with typical species of the atlantic areas and others more continental. The reserve also plays a role in a wildlife corridor.
The site consists of an old quarry of sandstone dated to the Famennian stage in the Late Devonian epoch. It was backfilled in the 1970s with marl. The new soil was re-colonized by pioneer species, which coexist alongside an established afforestation, forming a mosaic of habitats.
CPIE Bocage de l'Avesnois, a non-governmental organization, is the owner and operator of the reserve. The main objective is to maintain the current diversity. To this end, regular management mainly struggles against the afforestation and against invasive species, such as Japanese knot weed. The secondary objectives are environmental education, heritage interpretation, improvement of knowledge fauna and flora, and environmental monitoring.
Geography
Location
The Carrière des Nerviens Regional Nature Reserve is located in the Arrondissement of Avesnes-sur-Helpe between the cities of Valenciennes and Maubeuge, in the Nord department, Nord-Pas-de-Calais region. It is west of downtown Bavay and south-east of Saint-Waast.
The reserve is triangular in shape. It is bordered to the south by the 942 main road, north-east by an unused railtrack, and to the west by a small path known as . It covers . CPIE Bocage de l'Avesnois owns a parcel of land on the other side of the railtrack. Though not yet included in the reserve, it is expected to be added when the current agreement is renewed.
Relief
The reserve is located in the valley of the stream , with an elevation of between . It has an overall north-south gradient of . A mound of accumulated debris, which rises to about above the path , is located north-west of the site. After quarrying operations ceased, the quarry was filled mainly with the marl of the Bellignies quarry. The area has since been completely recolonized by vegetation through ecological succession.
Hydrology
The reserve is located in the valley of the , a tributary of the Hogneau, and is part of the greater drainage basin of the Scheldt. The reserve is not in direct contact with the river. It is supplied with water only by precipitation, which is retained by the natural properties of marl.
Climate
The reserve's nearest weather station is at Cambrai, about 42 kilometres away, inland, to the southeast. However, the nature reserve is affected by the nearby presence of the Ardennes Mountains, which gives a continental influence to the climate.
The regular precipitation and the absence of drought, as well as the predominance of south-southwest winds and rain vectors, show the influence of oceanic climate. However, some significant rainfall variability between seasons, the moderate temperature range, and the high proportion (69.8 percent) of low winds (less than ) compared to strong winds (3.2 percent over ) winds are typical of a continental influence. This combination is atypical of an altered oceanic climate, a transition zone between the oceanic and semi-continental climates, characterized by mild winters and cool summers.
In the reserve, this climatic transition leads to increased biodiversity. For example, common bluebell (Hyacinthoides non-scripta) is a typical species of the Atlantic areas, while the common butterbur (Petasites hybridus) is more continental.
History
Quarry
The site is a former quarry, used for its sandstone deposits as early as the late nineteenth century. by the Chevallier & Cie company, which employed about 70 workers, including 25 miners. In 1909, the annual production was of macadam, of ballast and of cobblestones.